Hydrocarbon conversion with a sulfided acidic multimetallic catalytic composite

ABSTRACT

Hydrocarbons are converted by contacting them at hydrocarbon conversion conditions with a sulfided acidic multimetallic catalytic composite comprising a combination of catalytically effective amounts of a platinum or palladium component, a rhodium component, a germanium component, a halogen component, and a sulfur component with a porous carrier material. The platinum or palladium, rhodium, germanium, halogen, and sulfur components are present in the multimetallic catalyst in amounts respectively, calculated on an elemental basis, corresponding to about 0.01 to about 2 wt. % platinum or palladium metal, about 0.01 to about 2 wt. % rhodium, about 0.01 to about 5 wt. % germanium, about 0.1 to about 3.5 wt. % halogen, and about 0.01 to about 1 wt. % sulfur. Moreover, the metallic components are uniformly dispersed throughout the porous carrier material in carefully controlled oxidation states such that substantially all of the platinum or palladium and rhodium components are present therein in a sulfided state or in a mixture of the sulfided state and the elemental metallic state and such that substantially all of the germanium component is present therein in an oxidation state above that of the elemental metal -- typically, as germanium oxide. The sulfiding of the catalytic composite is performed prior to any contact of the composite with hydrocarbon and after substantially all of the platinum or palladium and rhodium components have been reduced to the elemental metallic state by treatment with a sulfiding gas at conditions selected to incorporate about 0.01 to about 1 wt. % sulfur. The resulting sulfided and selectively prereduced catalyst has the capability of diminishing undesired demethylation and other hydrogenolysis reactions during initial operation of the process and markedly increasing the overall stability of the process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my prior copendingapplication Ser. No. 663,417 filed Mar. 3, 1976 and now abandoned; whichin turn is a division of my prior application Ser. No. 475,691 filedJune 3, 1974 and now U.S. Pat. No. 3,960,709; which in turn is acontinuation-in-part of may prior, now abandoned application Ser. No.391,428 filed Aug. 24, 1973 and now abandoned; which in turn is adivision of my prior application Ser. No. 225,634 filed Feb. 11, 1972and now U.S. Pat. No. 3,775,301; and which in turn is a division of myprior application Ser. No. 839,086 filed July 3, 1969 and now abandoned.All of the teachings of these prior applications are specificallyincorporated herein by reference.

The subject of the present invention is a novel sulfided acidicmultimetallic catalytic composite which has exceptional activity andresistance to deactivation when employed in a hydrocarbon conversionprocess that requires a catalyst having both ahydrogenation-dehydrogenation function and a cracking function. Moreprecisely, the present invention involves a novel dual-function sulfidedacidic multimetallic catalytic composite which, quite surprisingly,enables substantial improvements in hydrocarbon conversion processesthat have traditionally used a dual-function catalyst. In anotheraspect, the present invention comprehends the improved processes thatare produced by the use of a sulfided acidic catalytic compositecomprising a combination of catalytically effective amounts of aplatinum or palladium component, a rhodium component, a germaniumcomponent, a halogen component, and a sulfur component with a porouscarrier material; specifically, an improved reforming process whichutilizes the subject catalyst to improve activity, selectivity, andstability characteristics.

Composites having a hydrogenation-dehydrogenation function and acracking function are widely used today as catalysts in many industries,such as the petroleum and petrochemical industry, to accelerate a widespectrum of hydrocarbon conversion reactions. Generally, the crackingfunction is thought to be associated with an acid-acting material of theporous, adsorptive, refractory oxide type which is typically utilized asthe support or carrier for a heavy metal component such as the metals orcompounds of metals of Groups V through VIII of the Periodic Table towhich are generally attributed the hydrogenationdehydrogenationfunction.

These catalytic composites are used to accelerate a wide variety ofhydrocarbon conversion reactions such as hydrocracking, isomerization,dehydrogenation, hydrogenation, desulfurization, cyclization,polymerization, alkylation, cracking, hydroisomerization, etc. In manycases, the commercial applications of these catalysts are in processeswhere more than one of the reactions are proceeding simultaneously. Anexample of this type of process is reforming wherein a hydrocarbon feedstream containing paraffins and naphthenes is subjected to conditionswhich promote dehydrogenation of naphthenes to aromatics,dehydrocyclization of paraffins to aromatics, isomerization of paraffinsand naphthenes, hydrocracking of naphthenes and paraffins and the likereactions, to produce an octanerich or aromatic-rich product stream.Another example is a hydrocracking process wherein catalysts of thistype are utilized to effect selective hydrogenation and cracking of highmolecular weight unsaturated materials, selective hydrocracking of highmolecular weight materials, and other like reactions, to produce agenerally lower boiling, more valualbe output stream. Yet anotherexample is an isomerization process wherein a hydrocarbon fraction whichis relatively rich in straight-chain paraffin components is contactedwith a dual-function catalyst to produce an output stream rich inisoparaffin compounds.

Regardless of the reaction involved or the particular process involved,it is of critical importance that the dual-function catalyst exhibit notonly the capability to initially perform its specified functions, butalso that is has the capability to perform them satisfactorily forprolonged periods of time. The analytical terms used in the art tomeasure how well a particular catalyst performs its intended functionsin a particular hydrocarbon reaction environment are activity,selectivity, and stability. And for purposes of discussion here, theseterms are conveniently defined for a given charge stock as follows: (1)activity is a measure of the catalyst's ability to convert hydrocarbonreactants into products at a specified severity level where severitylevel means the conditions used -- that is, the temperature, pressure,contact time and presence of diluents such as H₂ ; (2) selectivityrefers to the amount of desired product or products obtained relative tothe amount of reactants charged or converted; (3) stability refers tothe rate of change with time of the activity and selectivity parameters-- obviously, the smaller rate implying the more stable catalyst. In areforming process, for example, activity commonly refers to the amountof conversion that takes place for a given charge stock at a specifiedseverity level and is typically measured by octane number of the C₅ +product stream; selectivity refers to the amount of C₅ + yield, relativeto the amount of the charge, that is obtained at the particular activityor severity level; and stability is typically equated to the rate ofchange with time of activity, as measured by octane number of C₅ +product, and of selectivity as measured by C₅ + yield. Actually, thelast statement is not strictly correct because generally a continuousreforming process is run to produce a constant octane C₅ + product withseverity level being continuously adjusted to attain this result; andfurthermore, the severity level is for this process usually varied byadjusting the conversion temperature in the reaction zone so that, inpoint of fact, the rate of change of activity finds response in the rateof change of conversion temperatures and changes in this last parameterare customarily taken as indicative of activity stability.

As is well known to those skilled in the art, the principal cause ofobserved deactivation or instability of a dual-function catalyst when itis used in a hydrocarbon conversion reaction is associated with the factthat coke forms on the surface of the catalyst during the course of thereaction. More specifically, in these hydrocarbon conversion processes,the conditions utilized typically result in the formation of heavy, highmolecular weight, black, solid or semi-solid, carbonaceous materialwhich is a hydrogen-deficient polymeric substance having properties akinto both polynuclear aromatics and graphite. This material coats thesurface of the catalyst and thus reduces its activity by shielding itsactive sites from the reactants. In other words, the performance of thisdual-function catalyst is sensitive to the presence of carbonaceousdeposits or coke on the surface of the catalyst. Accordingly, the majorproblem facing workers in this area of the art is the development ofmore active and selective catalytic composites that are not as sensitiveto the presence of these carbonaceous materials and/or have thecapability to suppress the rate of the formation of these carbonaceousmaterials on the catalyst. Viewed in terms of performance parameters,the problem is to develop a dual-function catalyst having superioractivity, selectivity and stability. In particular, for a reformingprocess the problem is typically expressed in terms of shifting andstabilizing the C₅ + yieldoctane relationship at the lowest possibleseverity level -- C₅ + yield being representative of selectivity andoctane being proportional to activity.

I have now found a dual-function sulfided acidic multimetallic catalyticcomposite which possesses improved activity, selectivity and stabilitycharacteristics when it is employed in a process for the conversion ofhydrocarbons of the type which have heretofore utilized dualfunctionacidic catalytic composites such as processes for isomerization,hydroisomerization, dehydrogenation, desulfurization, denitrogenization,hydrogenation, alkylation, dealkylation, disproportionation,polymerization, hydrodealkylation, transalkylation, cyclization,dehydrocyclization, cracking, hydrocracking, halogenation, reforming andthe like processes. In particular, I have ascertained that the judicioususe of a sulfided acidic catalyst, comprising a combination ofcatalytically effective amounts of a platinum or palladium component, arhodium component, a germanium component, a halogen component and asulfur component with a porous refractory carrier material, can enablethe performance of hydrocarbon conversion processes utilizingdual-function catalysts to be substantially improved if the metalliccomponents are uniformly dispersed throughout the carrier material, iftheir oxidation states are carefully controlled to be in the stateshereinafter specified, and if the catalyst is sulfided in the mannerindicated herein before use in the conversion of hydrocarbons and aftersubstantially all of the platinum or palladium and rhodium componentscontained therein are reduced to the elemental metallic state. I havedetermined, moreover, that a sulfided acidic catalytic composite,comprising a combination of catalytically effective amounts of aplatinum or palladium component, a germanium component, a rhodiumcomponent, a chloride component and a sulfur component with an aluminacarrier material, can be utilized to substantially improve theperformance of a reforming process which operates on a low-octanegasoline fraction to produce a high-octane and aromatic-rich reformateif the metallic components are uniformly dispersed throughout thealumina carrier material, if the oxidation states of the metalliccomponents are fixed in the states hereinafter specified and if thecatalyst is properly prereduced and sulfided before use in theconversion of hydrocarbons. In the case of a reforming process, theprincipal advantage associated with the use of the novel sulfided acidicmultimetallic catalyst of the present invention involves the acquisitionof the capability to operate in a stable manner in a high severityoperation; for example, a low pressure reforming process designed toproduce a C₅ + reformate having an octane of about 100 F-1 clear. Asindicated, the present invention essentially involves the finding thatthe careful addition of a sulfur component to a dual-function acidichydrocarbon conversion catalyst containing a platinum or palladiumcomponent, a rhodium component and a germanium component can enable theperformance characteristics of the catalyst to be sharply and materiallyimproved, if the hereinafter specified limitations on amounts ofingredients, oxidation states of metals, distribution of metalliccomponents in the support and sulfiding procedure are met.

It is accordingly one object of the present invention to provide animprovement in an acidic multimetallic hydrocarbon conversion catalysthaving superior performance characteristics when utilized in ahydrocarbon conversion process. A second object is to provide a sulfidedacidic catalyst having dual-function hydrocarbon conversion performancecharacteristics that are relatively insensitive to the deposition ofhydrocarbonaceuos material thereon. A third object is to providepreferred methods of preparation of this sulfided acidic multimetalliccatalytic composite which insures the achievement and maintenance of itsproperties. Another object is to provide an improved hydrocarbonreforming catalyst having superior activity, selectivity and stability.Yet another object is to provide a dual-function sulfided acidichydrocarbon conversion catalyst which utilizes a combination of agermanium component, a rhodium component and a sulfur component topromote and stabilize an acidic catalyst containing a platinum orpalladium component.

In brief summary, the present invention is, in one embodiment, asulfided acidic catalytic composite comprising a porous carrier materialcontaining, on an elemental basis, about 0.01 to about 2 wt. % platinumor palladium metal, about 0.01 to about 2 wt. % rhodium metal, about0.01 to about 5 wt. % germanium, about 0.1 to about 3.5 wt. % halogen,and about 0.01 to about 1 wt. % sulfur. Furthermore, the platinum orpalladium, germanium and rhodium are uniformly dispersed throughout theporous carrier material, substantially all of the platinum or palladiumand rhodium are present in a sulfided state or in a mixture of thesulfided state and the elemental metallic state, and substantially allof the germanium is present in an oxidation state above that of theelemental metal. A key feature is that the composite has been sulfided,prior to contact with hydrocarbon and after substantially all of theplatinum or palladium and rhodium contained therein have been reduced tothe elemental metallic state, by treatment with a sulfiding gas atconditions selected to incorporate about 0.01 to about 1 wt.% sulfur.

A second embodiment relates to a sulfided acidic catalytic compositecomprising a porous carrier material containing, on an elemental basis,about 0.05 to about 1 wt. % platinum or palladium metal, about 0.01 toabout 1 wt. % rhodium metal, about 0.05 to about 2 wt.% germanium, about0.5 to about 1.5 wt. % halogen and about 0.05 to 0.5 wt. % sulfur;wherein the platinum or palladium, rhodium and germanium are uniformlydispersed throughout the porous carrier material; wherein substantiallyall of the platinum or palladium and rhodium are present in a sulfidedstate or in a mixture of the sulfided state and the elemental metallicstate; wherein substantially all of the germanium is present in the formof germanium oxide; and wherein the composite has been sulfided, priorto contact with hydrocarbon and after substantially all of the platinumor palladium and rhodium contained therein have been reduced to theelemental metallic state, by treatment with a sulfiding gas atconditions selected to incorporate about 0.05 to 0.5 wt. % sulfur.

Another embodiment relates to a process for the conversion of ahydrocarbon comprising contacting the hydrocarbon and hydrogen with thesulfided acidic catalytic composite described above in the first orsecond embodiment at hydrocarbon conversion conditions.

A preferred embodiment relates to a process for reforming a gasolinefraction which comprises contacting the gasoline fraction and hydrogenwith the sulfided acidic catalytic composite described above in thefirst or second embodiment at reforming conditions selected to produce ahigh-octane reformate.

Other objects and embodiments of the present invention relate toadditional details regarding preferred catalytic ingredients, preferredamounts of ingredients, suitable methods of composite preparation,operating conditions for use in the hydrocarbon conversion processes,and the like particulars, which are hereinafter given in the followingdetailed discussion of each of these facets of the present invention.

The sulfided acidic multimetallic catalyst of the present inventioncomprises a porous carrier material or support having combined therewithcatalytically effective amounts of a platinum or palladium component, arhodium component, a germanium component, a halogen component and asulfur component.

Considering first the porous carrier material utilized in the presentinvention, it is preferred that the material be a porous, adsorptive,high-surface area support having a surface area of about 25 to about 500m² /g. The porous carrier material should be relatively refractory tothe conditions utilized in the hydrocarbon conversion process, and it isintended to include within the scope of the present invention carriermaterials which have traditionally been utilized in dual-functionhydrocarbon conversion catalysts such as: (1) activated carbon, coke orcharcoal; (2)silica or silica gel, silicon carbide, clays and silicatesincluding those synthetically prepared and naturally occurring, whichmay or may not be acid treated, for example, attapulgus clay, chinaclay, diatomaceous earth, fuller's earth, haolin, kieselguhr, etc., (3)ceramics, porcelain, crushed firebrick, buaxite; (4) refractoryinorganic oxides such as alumina, titanium dioxide, zirconium dioxide,chromium oxide, beryllium oxide, vanadium oxide, cesium oxide, hafniumoxide, zinc oxide, magnesia, boria, thoria, silica-alumina,silica-magnesia, chromia-alumina, alumina-boria, silica-zirconia, etc.;(5) cyrstalline zeolitic aluminosilicates such as naturally occurring orsynthetically prepared mordenite and/or faujasite, either in thehydrogen form or in a form which has been treated with multivalentcations; (6) spinels such as HgAl₂ O₄, FeAl₂ O₄, ZnAl₂ O ₄, MnAl₂ O₄,CaAl₂ O₄, and other like compounds having the formula MO.Al₂ O₃ where Mis a metal having a valence of 2; and (7) combinations of elements fromone or more of these groups. The preferred porous carrier materials foruse in the present invention are refractory inorganic oxides, with bestresults obtained with an alumina carrier material. Suitable aluminamaterials are the crystalline aluminas known as gamma-, eta- andtheta-alumine, with gamma- or eta-alumina giving best results. Inaddition, in some embodiments the alumina carrier material may containminor proportions of other well known refractory inorganic oxides suchas silica, zirconia, magnesia, etc.; however, the preferred support issubstantially pure gamma- or eta-alumina. Preferred carrier materialshave an apparent bulk density of about 0.3 to about 0.7 g/cc and surfacearea characteristics such that the average pore diameter is about 20 to300 Angstroms, the pore volume is about 0.1 to about 1 cc/g and thesurface area is about 100 to about 500 m² /g. In general, best resultsare typically obtained with a gamma-alumina carrier material which isused in the form of spherical particles having: a relatively smalldiameter (i.e. typically about 1/16 inch), an apparent bulk density ofabout 0.3 to about 0.8 g/cc, a pore volume of about 0.4 ml/g and asurface area of about 200 m² /g.

The preferred alumina carrier material may be prepared in any suitablemanner and may be synthetically prepared or natural occurring. Whatevertype of alumina is employed, it may be activated prior to use by one ormore treatments including drying, calcination, steaming, etc., and itmay be in a form known as activated alumina, activated alumina ofcommerce, porous alumina, alumina gel, etc. For example, the aluminacarrier may be prepared by adding a suitable alkaline reagent, such asammonium hydroxide, to a salt of aluminum such as aluminum chloride,aluminum nitrate, etc., in an amount to form an aluminum hydroxide gelwhich upon drying and calcining is converted to alumina. The aluminacarrier may be formed in any desired shape such as spheres, pills,cakes, extrudates, powders, granules, tablets, etc., and utilized in anydesired size. For the purpose of the present invention, a particularlypreferred form of alumina is the sphere; and alumina spheres may becontinuously manufactured by the well known oil drop method whichcomprises: forming an alumina hydrosol by any of the techniques taughtin the art and preferably by reacting aluminum metal with hydrochloricacid, combining the resultant hydrosol with a suitable gelling agent anddropping the resultant mixture into an oil bath maintained at elevatedtemperatures. The droplets of the mixture remain in the oil bath untilthey set and form hydrogel spheres. The spheres are then continuouslywithdrawn from the oil bath and typically subjected to specific agingtreatments in oil and an ammoniacal solution to further improve theirphysical characteristics. The resulting aged and gelled particles arethen washed and dried at a relatively low temperature of about 300° toabout 400° F. and subjected to a calcination procedure at a temperatureof about 850° F. to about 1300° F. for a period of about 1 to about 20hours. This treatment effects conversion of the alumina hydrogel to thecorresponding crystalline gamma-alumina. See the teachings of U.S. Pat.No. 2,620,314 for additional details.

One essential constituent of the sulfided multimetallic catalyst of thepresent invention is a germanium component. It is an essential featureof the present invention that substantially all of the germaniumcomponent is present in the catalyst in an oxidation state above that ofthe elemental metal. This component may exist within the composite as acompound such as the oxide, sulfide, halide, oxychloride, aluminate,etc., or in combination with the carrier material or other ingredientsof the composite. Although it is not intended to restrict the presentinvention by this explanation, it is believed that best results areobtained when the germanium component is present in the composite in the+2 or +4 oxidation state, with the +4 oxidation state being preferred.Preferably, the germanium component is used in an amount sufficient toresult in the final catalytic composite containing, on an elementalbasis, about 0.01 to about 5 wt. % germanium, with best resultstypically obtained with about 0.05 to about 2 wt. % germanium.

This germanium component may be incorporated in the catalytic compositein any suitable manner known to the art to result in a uniformdispersion of the metal moiety throughout the carrier material such asby coprecipitation or cogellation with the porous carrier material, ionexchange with the gelled carrier material, or impregnation of thecarrier material either after or before it is dried and calcined. It isto be noted that it is intended to include within the scope of thepresent invention all conventional methods for uniformly distributing ametallic component in a catalytic composite and the particular method ofincorporation used is not deemed to be an essential feature of thepresent invention. One method of incorporating the germanium componentinto the catalytic composite involves coprecipitating the germaniumcomponent during the preparation of the preferred carrier material,alumina. This method typically involves the addition of a suitablegermanium compound such as germanium tetrachloride or finely dividedgermanium oxide to the alumina hydrosol and then combining the hydrosolwith a suitable gelling agent and dropping the resulting mixture into anoil bath, etc., as explained in detail hereinbefore. After drying andcalcining the resulting gelled carrier material there is obtained anintimate combination of alumina and germanium oxide. A preferred methodof incorporating the germanium component into the catalytic compositeinvolves utilization of a soluble, decomposable compound of germanium toimpregnate the porous carrier material. In general, the solvent used inthis impregnation step is selected on the basis of the capability todissolve the desired germanium compound and is preferably an aqueous,acidic solution. Thus, the germanium component may be added to thecarrier material by commingling the latter with an aqueous, acidicsolution of suitable germanium salt or suitable compound of germaniumsuch as germanium oxide, germanium tetraethoxide, germaniumtetrapropoxide, germanium tetrachloride, germanium difluoride, germaniumtetrafluoride, germanium di-iodide, germanium monosulfide and the likecompounds. One particularly preferred impregnation solution comprisesnascent germanium metal dissolved in chlorine water to yield a germaniumoxychloride. A second preferred impregnation solution comprisesgermanium tetrachloride dissolved in an anhydrous alcohol such asethanol or propanol. In general, the germanium component can beimpregnated either prior to, simultaneously with, or after the othermetallic components are added to the carrier material. However, I havefound excellent results when the germanium component is impregnatedsimultaneously with the other metallic components. In fact, I havedetermined that a preferred impregnation solution compriseschloroplatinic acid, hydrogen chloride, rhodium trichloride hydrate, andgermanium tetrachloride dissolved in anhydrous ethanol or propanol. Bestresults are believed to be obtained when this component exists in thecomposite as germanium oxide.

A second essential ingredient of the subject catalyst is the platinum orpalladium component. That is, it is intended to cover the use ofplatinum or palladium or mixtures thereof as a second component of thepresent composite. It is an essential feature of the present inventionthat substantially all of this platinum or palladium component existswithin the final catalytic composite in the sulfided state or in amixture of the sulfided state and the elemental metallic state.Generally, the amount of this component present in the final catalyticcomposite is small compared to the quantities of the other componentscombined therewith. In fact, the platinum component generally willcomprise about 0.01 to about 2 wt. % of the final catalytic composite,calculated on an elemental basis. Excellent results are obtained whenthe catalyst contains about 0.05 to about 1 wt. % of platinum orpalladium metal.

This platinum or palladium component may be incorporated in thecatalytic composite in any suitable manner known to result in arelatively uniform distribution of this component in the carriermaterial such as coprecipitation or cogellation, ion exchange orimpregnation. The preferred method of preparing the catalyst involvesthe utilization of a soluble, decomposable compound of platinum orpalladium to impregnate the carrier material in a relatively uniformmanner. For example, this component may be added to the support bycommingling the latter with an aqueous solution of chloroplatinic orchloropalladic acid. Other water-soluble compounds of platinum orpalladium may be employed in impregnation solutions and include ammoniumchloroplatinate, bromoplatinic acid, platinum trichloride, platinumtetrachloride hydrate, platinum dichlorocarbonyl dichloride,dinitrodiaminoplatinum, sodium tetranitroplatinate (II), palladiumchloride, palladium nitrate, palladium sulfate, diaminepalladium (II)hydroxide, tetramminepalladium (II) chloride, etc. The utilization of aplatinum or palladium chloride compound, such as chloroplatinic orchloropalladic acid, is preferred since it facilitates the incorporationof both the platinum or palladium component and at least a minorquantity of the halogen component in a single step. Hydrogen chloride orthe like acid is also generally added to the impregnation solution inorder to further facilitate the incorporation of the halogen componentand the uniform distribution of the metallic components throughout thecarrier material. In addition, it is generally preferred to impregnatethe carrier material after it has been calcined in order to minimize therisk of washing away the valuable platinum or palladium compounds;however, in some cases it may be advantageous to impregnate the carriermaterial when it is in a gelled state.

Yet another essential ingredient of the present catalytic composite is arhodium component. It is of fundamental importance that substantiallyall of the rhodium component exists within the catalytic composite ofthe present invention in a sulfided state or in a mixture of theelemental metallic state and the sulfided state. The rhodium componentmay be utilized in the composite in any amount which is catalyticallyeffective, with the preferred amount being about 0.01 to about 2 wt. %thereof, calculated on an elemental basis. Typically, best results areobtained with about 0.01 to about 1 wt. % rhodium. It is additionallypreferred to select the specified amount of rhodium from within thisbroad weight range as a function of the amount of the platinum orpalladium component, on an atomic basis, as is explained hereinafter.

This rhodium component may be incorporated into the catalytic compositein any suitable manner known to those skilled in the catalystformulation art which results in a relatively uniform distribution ofrhodium in the carrier material. In addition, it may be added at anystage of the preparation of the composite -- either during preparationof the carrier material or thereafter -- and the precise method ofincorporation used is not deemed to be critical. However, best resultsare obtained when the rhodium component is relatively uniformlydistributed throughout the carrier material, and the preferredprocedures are the ones known to result in a composite having thisrelatively uniform distribution. One acceptable procedure forincorporating this component into the composite involves cogelling orcoprecipitating the rhodium component during the preparation of thepreferred carrier material, alumina. This procedure usually comprehendsthe addition of a soluble, decomposable compound of rhodium such asrhodium trichloride hydrate to the alumina hydrosol before it is gelled.The resulting mixture is then finished by conventional gelling, aging,drying and calcination steps as explained hereinbefore. A preferred wayof incorporating this component is an impregnation step wherein theporous carrier material is impregnated with a suitablerhodium-containing solution either before, during or after the carriermaterial is calcined. Preferred impregnation solutions are aqueoussolutions of water soluble, decomposable rhodium compounds such ashexamminerhodium chloride, rhodium carbonylchloride, rhodium trichloridehydrate, rhodium nitrate, sodium hexachlororhodate (III), sodiumhexanitrorhodate (III), rhodium sulfate and the like compounds. Bestresults are ordinarily obtained when the impregnation solution is anaqueous solution of rhodium trichloride hydrate or rhodium nitrate. Thiscomponent can be added to the carrier material either prior to,simultaneously with, or after the other metallic components are combinedtherewith. Best results are usually achieved when this component isadded simultaneously with the other metallic components. In fact,excellent results are obtained, as reported in the examples, with aone-step impregnation procedure using an aqueous solution comprisingchloroplatinic or chloropalladic acid, rhodium trichloride hydrate,hydrochloric acid and germanium tetrachloride dissolved in anhydrousalcohol.

It is essential to incorporate a halogen component into the sulfidedacidic catalytic composite of the present invention. Although theprecise form of the chemistry of the association of the halogencomponent with the carrier material is not entirely known, it iscustomary in the art to refer to the halogen component as being combinedwith the carrier material, or with the other ingredients of the catalystin the form of the halide (e.g. as the chloride). This combined halogenmay be either fluorine, chlorine, iodine, bromine, or mixtures thereof.Of these, fluorine and particularly chlorine are preferred for thepurposes of the present invention. The halogen may be added to thecarrier material in any suitable manner, either during preparation ofthe support or before or after the addition of the other components. Forexample, the halogen may be added, at any stage of the preparation ofthe carrier material or to the calcined carrier material, as an aqueoussolution of a suitable, decomposable halogen-containing compound such ashydrogen fluoride, hydrogen chloride, hydrogen bromide, ammoniumchloride, etc. The halogen component or a portion thereof, may becombined with the carrier material during the impregnation of the latterwith the platinum or palladium and rhodium components; for example,through the utilization of a mixture of chloroplatinic acid and hydrogenchloride. In another situation, the alumina hydrosol which is typicallyutilized to form the preferred alumina carrier material may containhalogen and thus contribute at least a portion of the halogen componentto the final composite. For reforming, the halogen will be typicallycombined with the carrier material in an amount sufficient to result ina final composite that contains about 0.1 to about 3.5%, and preferablyabout 0.5 to about 1.5% by weight, of halogen, calculated on anelemental basis. In isomerization or hydrocracking embodiments, it isgenerally preferred to utilize relatively larger amounts of halogen inthe catalyst -- typically ranging up to about 10 wt. % halogencalculated on an elemental basis, and more preferably, about 1 to about5 wt. %. It is to be understood that the specified level of halogencomponent in the instant catalyst can be achieved or maintained duringuse in the conversion of hydrocarbons by continuously or periodicallyadding to the reaction zone a decomposable halogen-containing compoundsuch as an organic chloride (e.g. ethylene dichloride, carbontetrachloride, t-butyl chloride) in an amount of about 1 to 100 wt. ppm.of the hydrocarbon feed, and preferably about 1 to 10 wt. ppm.

Regarding the preferred amounts of the various metallic components ofthe subject catalyst, I have found it to be a good practice to specifythe amounts of the rhodium component and the germanium component as afunction of the amount of the platinum or palladium component. On thisbasis, the amount of the rhodium component is ordinarily selected sothat the atomic ratio of rhodium to platinum or palladium metalcontained in the composite is about 0.1:1 to about 2:1, with thepreferred range being about 0.25:1 to about 1.5:1. Similarly, the amountof the germanium component is ordinarily selected to produce a compositecontaining an atomic ratio of germanium to platinum or palladium metalof about 0.3:1 to about 10:1, with the preferred range being about 0.6:1to about 6:1.

Another significant parameter for the instant catalyst is the "totalmetals content" which is defined to be the sum of the platinum orpalladium component, the rhodium component and the germanium component,calculated on an elemental basis. Good results are ordinarily obtainedwith the subject catalyst when this parameter is fixed at a value ofabout 0.15 to about 3 wt. %, with best results ordinarily achieved at ametals loading of about 0.3 to about 2 wt. %.

In embodiments of the present invention wherein the instant sulfidedmultimetallic catalytic composite is used for the dehydrogenation ofdehydrogenatable hydrocarbons or for the hydrogenation of hydrogenatablehydrocarbons, it is ordinarily a preferred practice to include an alkalior alkaline earth metal component in the composite and to minimize oreliminate the halogen component. More precisely, this optionalingredient is selected from the group consisting of the compounds of thealkali metals -- cesium, rubidium, potassium, sodium, and lithium -- andthe compounds of the alkaline earth metals -- calcium, strontium, bariumand magnesium. Generally, good results are obtained in these embodimentswhen this component constitutes about 0.1 to about 5 wt. % of thecomposite, calculated on an elemental basis. This optional alkali oralkaline earth metal component can be incorporated in the composite inany of the known ways, with impregnation with an aqueous solution of asuitable water-soluble, decomposable compound being preferred.

An optional ingredient for the sulfided multimetallic catalyst of thepresent invention is a Friedel-Crafts metal halide component. Thisingredient is particularly useful in hydrocarbon conversion embodimentsof the present invention wherein it is preferred that the catalystutilized has a strong acid or cracking function associated therewith --for example, an embodiment wherein hydrocarbons are to be hydrocrackedor isomerized with the catalyst of the present invention. Suitable metalhalides of the Friedel-Crafts type include aluminum chloride, aluminumbromide, ferric chloride, ferric bromide, zinc chloride and the likecompounds, with the aluminum halides and particularly aluminum chlorideordinarily yielding best results. Generally, this optional ingredientcan be incorporated into the composite of the present invention by anyof the conventional methods for adding metallic halides of this type;however, best results are ordinarily obtained when the metallic halideis sublimed onto the surface of the carrier material according to thepreferred method disclosed in U.S. Pat. No. 2,999,074. The component cangenerally be utilized in any amount which is catalytically effective,with a value selected from the range of about 1 to about 100 wt. % ofthe carrier material generally being preferred.

Regardless of the details of how the components of the catalyst arecombined with the porous carrier material, the final catalyst generallywill be dried at a temperature of about 200° to about 600° F. for aperiod of at least about 2 to about 24 hours or more, and finallycalcined or oxidized at a temperature of about 700° to about 1100° F. inan air or oxygen atmosphere for a period of about 0.5 to about 10 hoursin order to convert substantially all of the metallic componentssubstantially to the corresponding oxide form. Because a halogencomponent is utilized in the catalyst, best results are generallyobtained when the halogen content of the catalyst is adjusted during thecalcination step by including a halogen or a halogencontaining compoundsuch as HCl in the air or oxygen atmosphere utilized. In particular,when the halogen component of the catalyst is chlorine, it is preferredto use a mole ratio of H₂ O to HCl of about 5:1 to about 100:1 during atleast a portion of the calcination step in order to adjust the finalchlorine content of the catalyst to a range of about 0.1 to about 3.5wt. %.

It is an essential feature of the present invention that the resultantoxidized catalytic composite is subjected to a substantially water-freereduction step prior to its use in the conversion of hydrocarbons. Thisstep is designed to selectively reduce the platinum or palladium andrhodium components to the corresponding metals and to insure a uniformand finely divided dispersion of these metallic components throughoutthe carrier material, while maintaining the germanium component in apositive oxidation state. Preferably, a substantially pure and dryhydrogen stream (i.e. less than 20 vol. ppm. H₂ O) is used as thereducing agent in this step. The reducing agent is contacted with theoxidized catalyst at conditions including a temperature of about 400° toabout 1200° F. and a period of time of about 0.5 to 10 hours effectiveto reduce substantially all of the platinum or palladium and rhodiumcomponents to the elemental metallic state, while maintaining thegermanium compoent in an oxide state. This reduction treatment may beperformed in situ as part of a start-up sequence if precautions aretaken to predry the plant to a substantially water-free state and if asubstantially water-free hydrogen stream is used.

Another essential feature of the instant invention involves recognitionthat the resulting selectively reduced catalytic composite can bebeneficially subjected to a presulfiding operation with a sulfidingreagent designed to incorporate in the catalytic composite from about0.01 to about 1 and more preferably about 0.05 to about 0.5 wt. %sulfur, calculated on an elemental basis. I have found that it iscrucial to perform this presulfiding procedure prior to use of thecatalytic composite in the conversion of hydrocarbons and aftersubstantially all of the platinum or palladium and rhodium componentshave been reduced to the elemental metallic state. The principal reasonfor this requirement is that it ensures that the uniform distribution ofrelatively small crystallites of the metallic components in the carriermaterial will not be adversely affected by the sulfiding reagent or byuncontrollable exothermic hydrogenolysis reactions during start-up ofthe hydrocarbon conversion process. Preferably, this presulfidingtreatment takes place in the presence of hydrogen and a suitablesulfur-containing decomposable sulfiding reagent such as hydrogensulfide, lower molecular weight mercaptans, organic sulfides anddisulfides, etc. Typically, this procedure comprises treating theselectively reduced catalyst with a sulfiding gas such as a mixture ofhydrogen and hydrogen sulfide in a mole ratio of hydrogen to hydrogensulfide of about 1:1 to about 50:1, and preferably about 5:1 to about15:1, at conditions sufficient to effect the desired incorporation ofsulfur, generally including a temperature ranging from about 50° up toabout 1100° F. or more. It is generally a good practice to perform thispresulfiding step under substantially water-free conditions. It iswithin the scope of the present invention to maintain the sulfided stateof the instant catalyst during use in the conversion of hydrocarbons bycontinuously or periodically adding a decomposable sulfur-containingcompound, such as the sulfiding reagents previously mentioned, to thereactor containing the catalyst in an amount sufficient to provide about1 to 500 wt. ppm., preferably 1 to 20 wt. ppm. of sulfur based onhydrocarbon charge.

According to the present invention, a hydrocarbon charge stock andhydrogen are contacted with the sulfided acidic catalyst in ahydrocarbon conversion zone. This contacting may be accomplished byusing the catalyst in a fixed bed system, a moving bed system, afluidized bed system, or in a batch type operation; however, in view ofthe danger of attrition losses of the valuable catalyst and of wellknown operational advantages, it is preferrred to use a fixed bedsystem. In this system, a hydrogen-rich gas and the charge stock arepreheated by any suitable heating means to the desired reactiontemperature and then are passed into a conversion zone containing afixed bed of the catalyst type previously characterized. It is, ofcourse, understood that the conversion zone may be one or more separatereactors with suitable means therebetween to insure that the desiredconversion temperature is maintained at the entrance to each reactor. Itis also important to note that the reactants may be contacted with thecatalyst bed in either upward, downward, or radial flow fashion with thelatter being preferred. In addition, the reactants may be in the liquidphase, a mixed liquid-vapor phase, or a vapor phase when they contactthe catalyst, with best results obtained in the vapor phase.

In the case where the sulfided acidic catalyst of the present inventionis used in a reforming operation, the reforming system will comprise areforming zone containing a fixed bed of the catalyst type previouslycharacterized. This reforming zone may be one or more separate reactorswith suitable heating means therebetween to compensate for theendothermic nature of the reactions that take place in each catalystbed. The hydrocarbon feed stream that is charged to this reformingsystem will comprise hydrocarbon fractions containing naphthenes andparaffins that boil within the gasoline range. The preferred chargestocks are those consisting essentially of naphthenes and paraffins,although in some cases aromatics and/or olefins may also be present.This preferred class includes straight run gasolines, natural gasolines,synthetic gasolines, partially reformed gasolines and the like. On theother hand, it is frequently advantageous to charge thermally orcatalytically cracked gasolines or higher boiling fractions thereof.Mixtures of straight run and cracked gasolines can also be used toadvantage. The gasoline charge stock may be a full boiling gasolinehaving an initial boiling point of from about 50° to about 150° F. andan end boiling point within the range of from about 325° to about 425°F., or may be a selected fraction thereof which generally will be ahigher boiling fraction commonly referred to as a heavy naphtha -- forexample, a naphtha boiling in the range of C₇ to 400° F. In some cases,it is also advantageous to charge pure hydrocarbons or mixtures ofhydrocarbons that have been extracted from hydrocarbon distillates --for example, straight-chain paraffins -- which are to be converted toaromatics. It is preferred that these charge stocks be treated byconventinal catalytic pretreatment methods such as hydrorefining.,hydrotreating, hydrodefulfurization, etc., to remove substantially allsulfurous, nitrogenous and water-yielding contaminants therefrom and tosaturate any olefins that may be contained therein.

In other hydrocarbon conversion embodiments, the charge stock will be ofthe conventional type customarily used for the particular kind ofhydrocarbon conversion being effected. For example, in a typicalisomerization embodiment the charge stock can be a paraffinic stock richin C₄ to C₈ normal paraffins, or a normal butane-rich stock or ann-hexane-rich stock, or a mixture of xylene isomers, or an ofein-richstock, etc. In a dehydrogenation embodiment, the charge stock can be anyof the known dehydrogenatable hydrocarbons such as an aliphatic compoundcontaining 2 to 30 carbon atoms per molecule, a C₄ to C₃₀ normalparaffin, a C₈ to C₁₂ alkylaromatic, a naphthene and the like. Inhydrocracking embodiments, the charge stock will be typically a gas oil,heavy cracked cycle oil, etc. In addition, alkylaromatic, olefins andnaphthenes can be conveniently isomerized by using the catalyst of thepresent invention. Likewise, pure hydrocarbons or substantially purehydrocarbons can be converted to more valuable products by using thesulfided acidic catalyst of the present invention in any of thehydrocarbon conversion processes, known to the art, that use a dualfunction catalyst.

In a reforming embodiment, it is generally preferred to utilize thesulfided acidic catalytic composite in a substantially water-freeenvironment. Essential to the achievement of this condition in thereforming zone is the control of the water level present in the chargestock and the hydrogen stream which is being charged to the reformingreaction zone. Best results are ordinarily obtained when the totalamount of water entering the conversion zone from any source is held toa level less than 50 ppm. and preferably less than 20 ppm. expressed asweight of equivalent water in the charge stock. In general, this can beaccomplished by careful control of the water present in the charge stockand in the hydrogen stream. The charge stock can be dried by using anysuitable drying means known to the art, such as a conventional solidadsorbent having a high selectivity for water, for instance, sodium orcalcium crystalline aluminosilicates, silica gel, activated alumina,molecular sieves, anhydrous calcium sulfate, high surface area sodiumand the like adsorbents. Similarly, the water content of the chargestock may be adjusted by suitable stripping operations in afractionation column or like device. And in some cases, a combination ofadsorbent drying and distillation drying may be used advantageously toeffect almost complete removal of water from the charge stock.Preferably the charge stock is dried to a level corresponding to lesstha 20 ppm. of H₂ O equivalent. In general, it is preferred to maintainthe hydrogen stream entering the hydrocarbon conversion zone at a levelof about 10 vol. ppm. of water or less. If the water level in thehydrogen stream is too high, drying of same can be convenientlyaccomplished by contacting the hydrogen stream with a suitable desiccantsuch as those mentioned above.

In the reforming embodiment, an effluent stream is withdrawn from thereforming zone and passed through a cooling means to a separation zone,typically maintained at about 25° to 150° F., wherein a hydrogen-richgas is separated from a high octane liquid product, commonly called anunstabilized reformate. When a super-dry operation is desired, at leasta portion of this hydrogen-rich gas is withdrawn from the separatingzone and passed through an adsorption zone containing an absorbentselective for water. The resultant substantially water-free hydrogenstream can then be recycled through suitable compressing means back tothe reforming zone. The liquid phase from the separating zone istypically withdrawn and commonly treated in a fractionating system inorder to adjust the butane concentration, thereby controlling front-endvolatility of the resulting reformate.

The conditions utilized in the numerous hydrocarbon conversionembodiments of the present invention are those customarily used in theart for the particular reaction, or combination of reactions, that is tobe effected. For instance, alkylaromatic, olefin, and paraffinisomerization conditions include: a temperature of about 32° to about1000° F. and preferably from about 75° to about 600° F.; a pressure ofatmospheric to about 100 atmospheres; a hydrogen to hydrocarbon moleratio of about 0.5:1 to about 20:1 and an LHSV (calculated on the basisof equivalent liquid volume of the charge stock contacted with thecatalyst per hour divided by the volume of conversion zone containingcatalyst) of about 0.2 hr.⁻¹ to 10 hr.⁻¹. Dehydrogenation conditionsinclude: a temperature of about 700° to about 1250° F., a pressure ofabout 0.1 to about 10 atmospheres, a liquid hourly space velocity ofabout 1 to 40 hr.⁻¹ and a hydrogen to hydrocarbon mole ratio of about1:1 to 20:1. Likewise, typically hydrocracking conditions include: apressure of about 500 psig. to about 3000 psig., a temperature of about400° to about 900° F., an LHSV of about 0.1 hr.⁻¹ to about 10 hr.⁻¹, andhydrogen circulation rates of about 1000 to 10,000 SCF per barrel ofcharge.

In the reforming embodiment of the present invention, the pressureutilized is selected from the range of about 0 psig. to about 1000psig., with the preferred pressure being about 50 psig. to about 600psig. Particularly good results are obtained at low pressure; namely, apressure of about 50 to 350 psig. In fact, it is a singular advantage ofthe present invention that it allows stable operation at lower pressurethan have heretofore been successfully utilized in so-called"continuous" reforming systems (i.e. reforming for periods of about 15to about 200 or more barrels of charge per pound of catalyst withoutregeneration) with all platinum monometallic catalyst. In other words,the sulfided acidic catalyst of the present invention allows theoperation of a continuous reforming system to be conducted at lowerpressure (i.e. 100 to about 350 psig.) for about the same or bettercatalyst life before regeneration as has been heretofore realized withconventional monometallic catalysts at higher pressures (i.e. 400 to 600psig.). On the other hand, the stability feature of the presentinvention enables reforming operations conducted at pressures of 400 to600 psig. to achieve substantially increased catalyst life beforeregeneration.

Similarly, the temperature required for reforming is generally lowerthan that required for a similar reforming operation using a highquality catalyst of the prior art. This significant and desirablefeature of the present invention is a consequence of the selectivity ofthe sulfided acidic catalyst of the present invention for theoctane-upgrading reactions that are preferably induced in a typicalreforming operation. Hence, the present invention requires a temperaturein the range of from about 800° to about 1100° F. and preferably about900° to about 1050° F. As is well known to those skilled in thecontinuous reforming art, the initial selection of the temperaturewithin this broad range is made primarily as a function of the desiredoctane of the product reformate considering the characteristics of thecharge stock and of the catalyst. Ordinarily, the temperature then isthereafter slowly increased during the run to compensate for theinevitable deactivation that occurs to provide a constant octaneproduct. Therefore, it is a feature of the present invention that therate at which the temperature is increased in order to maintain aconstant octane product is substantially lower for the catalyst of thepresent invention than for a high quality reforming catalyst which ismanufactured in exactly the same manner as the catalyst of the presentinvention except for the inclusion of the rhodium and germaniumcomponents. Moreover, for the catalyst of the present invention, theC₅ + yield loss for a given temperature increase is substantially lowerthan for this high quality reforming catalyst of the prior art.

The reforming embodiment of the present invention also typicallyutilizes sufficient hydrogen to provide an amount of about 1 to about 20moles of hydrogen per mole of hydrocarbon entering the reforming zone,with excellent results being obtained when about 5 to about 10 moles ofhydrogen are used per mole of hydrocarbon. Likewise, the liquid hourlyspace velocity (LHSV) used in reforming is selected from the range ofabout 0.1 to about 10 hr.⁻¹, with a value in the range of about 1 toabout 5 hr.⁻¹ being preferred. In fact, it is a feature of the presentinvention that it allows operations to be conducted at higher LHSV thannormally can be stably achieved in a continuous reforming process with ahigh quality reforming catalyst of the prior art. This last feature isof immense economic significance because it allows a continuousreforming process to operate at the same throughput level with lesscatalyst inventory than that heretofore used with conventional reformingcatalysts at no sacrifice in catalyst life before regeneration.

The following working examples are given to illustrate further thepreparation of the sulfided acidic catalytic composite of the presentinvention and the use thereof in the conversion of hydrocarbons. It isunderstood that the examples are intended to be illustrative rather thanrestrictive.

EXAMPLE I

An alumina carrier material comprising 1/16 inch spheres is prepared by:forming an aluminum hydroxyl chloride sol by dissolving substantiallypure aluminum pellets in a hydrochloric acid solution, addinghexamethylenetetramine to the resulting alumina sol, gelling theresulting solution by dropping it into a hot oil bath to form sphericalparticles of an alumina hydrogel, aging and washing the resultingparticles, and finally drying and calcining the aged and washedparticles to form spherical particles of gamma-alumina containing about0.3 wt. % combined chloride. Additional details as to this method ofpreparing the preferred carrier material are given in the teachings ofU.S. Pat. No. 2,620,314.

A measured amount of germanium tetrachloride is dissolved in anhydrousethanol and the resulting solution is then aged at room temperatureuntil an equilibrium condition is established therein. An aqueousimpregnation solution containing chloroplatinic acid, rhodiumtrichloride hydrate, and hydrogen chloride in admixture with the agedgermanium-containing alcoholic solution is then prepared. Thisimpregnation solution is then intimately admixed with the gamma-aluminaparticles. The amounts of the metallic reagents in this solution arecarefully selected to result in a final composite containing, on anelemental basis, 0.375 wt. % platinum, 0.1 wt. % rhodium and 0.5 wt. %germanium. In order to insure uniform distribution of the metalliccomponents throughout the carrier material, the amount of hydrogenchloride corresponds to about 2 wt. % of the alumina particles. Thisimpregnation step is performed by adding the carrier material particlesto the impregnation mixture with constant agitation. In addition, thevolume of the solution is approximately the same as the volume of thecarrier material particles. The impregnation mixture is maintained incontact with the carrier material particles for a period of about 1/2 toabout 3 hours at a temperature of about 70° F. Thereafter, thetemperature of the impregnation mixture is raised to about 225° F. andthe excess solution is evaporated in a period of about 1 hour. Theresulting dried particles are then subjected to an oxidation treatmentwith a sulfur-free dry air stream at a temperature of about 975° F., aGHSV of about 500 hr.⁻¹, and atmospheric pressure for about 1/2 hour.The oxidized spheres are then contacted with a sulfur-free air streamcontaining H₂ O and HCl in a mole ratio of about 30:1 for about 2 hoursat 975° F. and a GHSV of 500 hr.⁻¹ in order to adjust the halogencontent of the catalyst particles to a value of about 1 wt. %.

The resulting oxidized catalyst particles are analyzed and found tocontain, on an elemental basis, about 0.375 wt. % platinum, about 0.1wt. % rhodium, about 0.5 wt. % germanium and about 1 wt. % chloride. Forthis catalyst, the atomic ratio of germanium to platinum is 3.58:1 andthe atomic ratio of rhodium to platinum is 0.5:1.

Thereafter, the oxidized and halogen treated catalyst particles aresubjected to a dry prereduction treatment designed to reducesubstantially all of the platinum and rhodium components to theelemental metallic state while maintaining the germanium component in anoxide state by contacting them for 1 hour with a substantiallysulfur-free hydrogen stream containing less than 5 vol. ppm. H₂ O at atemperature of about 1050° F., a pressure slightly above atmospheric anda flow rate of the hydrogen stream through the catalyst particlescorresponding to a gas hourly space velocity of about 400 hr.⁻¹.

The resulting selectively reduced catalyst particles are then contactedwith a water-free sulfiding gas comprising a mixture of H₂ S and H₂ in amole ratio of about 10:1 moles of H₂ per mole of H₂ S at a temperatureof about 1050° F., atmospheric pressure and a GHSV of about 800 hr.⁻¹for a period of about 1/2 hour effective to incorporate about 0.2 wt. %sulfur which is primarily present in the form of a mixture of platinumsulfide and rhodium sulfide.

EXAMPLE II

A portion of the spherical sulfided acidic catalyst particles producedby the method described in Example I is loaded into a scale model of acontinuous, fixed bed reforming plant of conventional design. In thisplant a heavy Kuwait naphtha and hydrogen are continuously contacted atreforming conditions: a liquid hourly space velocity of 1.5 hr.⁻¹, apressure of 100 psig., a hydrogen-containing recycle gas to hydrocarbonmole ratio of 6:1, and a temperature sufficient to continuously producea C₅ + reformate of 102 F-1 clear. It is to be noted that these areexceptionally severe conditions.

The heavy Kuwait naphtha has an API gravity at 60° F. of 60.4, aninitial boiling point of 184° F., a 50% boiling point of 256° F., and anend boiling point of 360° F. In addition, it contains about 8 vol. %aromatics, 71 vol. % paraffins, 21 vol. % naphthenes, 0.5 wt. parts permillion sulfur, and 5 to 8 wt. parts per million water. The F-1 clearoctane number of the raw stock is 40.0.

The fixed bed reforming plant is made up of a reactor containing thesulfided acidic catalyst, a hydrogen separation zone, a debutanizercolumn, and suitable heating, pumping, cooling and controlling means. Inthis plant, a hydrogen recycle stream and the charge stock arecommingled and heated to the desired temperature. The resultant mixtureis then passed downflow into a reactor containing the subject sulfidedcatalyst as a fixed bed. An effluent stream is then withdrawn from thebottom of the reactor, cooled to about 55° F. and passed to a separatingzone wherein a hydrogen-rich gaseous phase separates from a liquidhydrocarbon phase. A portion of the gaseous phase is continuously passedthrough a high surface area sodium scrubber and the resulting water-freehydrogen-containing gas stream recycled to the reactor in order tosupply hydrogen thereto, and the excess gaseous phase over that neededfor plant pressure is recovered as excess separator gas. The liquidhydrocarbon phase from the hydrogen separating zone is withdrawntherefrom and passed to a debutanizer column of conventional designwherein light ends are taken overhead as debutanizer gas and a C₅ +reformate stream recovered as bottoms.

The test run is continued for a catalyst life of about 20 barrels ofcharge per pound of catalyst utilized, and it is determined that theactivity, selectivity and stability of the present sulfided acidicmultimetallic catalyst are vastly superior to those observed in asimilar type test with a conventional commercial reforming catalyst.More specifically, the results obtained from the subject catalyst aresuperior to the platinum metal-containing catalyst of the prior art inthe areas of overage temperature required to make octane, average C₅ +yield at octane, rate of temperature increase necessary to maintainoctane, and C₅ + yield decline rate. Also it is noted that the principaleffect of the sulfiding step on the performance of the instant catalystinvolves greatly diminished undesired exothermic demethylation and otherhydrogenolysis activity during the initial portion of the test run andmarkedly increased overall stability.

It is intended to cover by the following claims all changes andmodifications of the above disclosure of the present invention whichwould be self-evident to a man of ordinary skill in the catalystformulation art or the hydrocarbon conversion art.

I claim as my invention:
 1. A process for converting a hydrocarbon whichcomprises contacting the hydrocarbon at hydrocarbon conversionconditions with a sulfided acidic catalytic composite comprising aporous carrier material containing, on an elemental basis, about 0.01 toabout 2 wt. % platinum or palladium, about 0.01 to about 2 wt. %rhodium, about 0.01 to about 5 wt. % germanium, about 0.1 to about 3.5wt. % halogen, and about 0.01 to about 1 wt. % sulfur; wherein theplatinum or palladium, rhodium and germanium are uniformly dispersedthroughout the porous carrier material; wherein substantially all of theplatinum or palladium and rhodium are present in a sulfided state or ina mixture of the sulfided state and the elemental metallic state;wherein substantially all of the germanium is present in an oxidationstate above that of the elemental metal; and wherein the composite hasbeen sulfided, prior to contact with the hydrocarbon and aftersubstantially all of the platinum or palladium and rhodium containedtherein have been reduced to the elemental metallic state, by treatmentwith a sulfiding gas at conditions selected to incorporate about 0.01 toabout 1 wt. % sulfur.
 2. A process as defined in claim 1 wherein theporous carrier material is a refractory inorganic oxide.
 3. A process asdefined in claim 2 wherein the refractory inorganic oxide is alumina. 4.A process as defined in claim 1 wherein the halogen is combinedchloride.
 5. A process as defined in claim 1 wherein substantially allof the germanium is present in the catalytic composite in the form ofgermanium oxide.
 6. A process as defined in claim 1 wherein the atomicratio of germanium to platinum or palladium contained in the compositeis about 0.3:1 to about 10:1.
 7. A process as defined in claim 1 whereinthe atomic ratio of rhodium to platinum or palladium contained in thecomposite is about 0.1:1 to about 2:1.
 8. A process as defined in claim1 wherein the sulfiding gas is a mixture of hydrogen and hydrogensulfide.
 9. A process as defined in claim 1 wherein the compositecontains about 0.05 to about 1 wt. % platinum or palladium, about 0.01to about 1 wt. % rhodium, about 0.05 to about 2 wt. % germanium, about0.5 to about 1.5 wt. % halogen, and about 0.05 to about 0.5 wt. %sulfur.
 10. A process as defined in claim 1 wherein the contacting ofthe hydrocarbon with the catalytic composite is performed in thepresence of hydrogen.
 11. A process as defined in claim 1 wherein thetype of hydrocarbon conversion is catalytic reforming of a gasolinefraction to produce a high octane reformate, wherein the hydrocarbon iscontained in the gasoline fraction, wherein the contacting is performedin the presence of hydrogen, and wherein the hydrocarbon conversionconditions are reforming conditions.
 12. A process as defined in claim11 wherein the reforming conditions include a temperature of about 800to about 1100° F., a pressure of about 0 to about 1000 psig., a liquidhourly space velocity of about 0.1 to about 10 hr.⁻¹, and a mole ratioof hydrogen to hydrocarbon of about 1:1 to about 20:1.
 13. A process asdefined in claim 11 wherein the contacting is performed in asubstantially water-free environment.
 14. A process as defined in claim11 wherein the reforming conditions include a pressure of about 50 toabout 350 psig.
 15. A process as defined in claim 9 wherein the type ofhydrocarbon conversion is catalytic reforming of a gasoline fraction toproduce a high octane reformate, wherein the hydrocarbon is contained inthe gasoline fraction, wherein the contacting is performed in thepresence of hydrogen and wherein the hydrocarbon conversion conditionsare reforming conditions.
 16. A sulfided acidic catalytic compositecomprising a porous carrier material containing, on an elemental basis,about 0.01 to about 2 wt. % platinum or palladium, about 0.01 to about 2wt. % rhodium, about 0.01 to about 5 wt. % germanium, about 0.1 to about3.5 wt. % halogen, and about 0.01 to about 1 wt. % sulfur; wherein theplatinum or palladium, rhodium and germanium are uniformly dispersedthroughout the porous carrier material; wherein substantially all of theplatinum or palladium and rhodium are present in a sulfided state or ina mixture of the sulfided state and the elemental metallic state;wherein substantially all of the germanium is present in an oxidationstate above that of the elemental metal; and wherein the composite hasbeen sulfided, prior to contact with hydrocarbon and after substantiallyall of the platinum or palladium and rhodium contained therein have beenreduced to the elemental metallic state, by treating with a sulfidinggas at conditions selected to incorporate about 0.01 to about 1 wt. %sulfur.